Process of preparing stabilized chlorinated rubbers



Patented Mar. 12, 1935' Uu rso [STAT-ES "PA-Tear OFFICE PROCESSorraaraamo srannirza'p emomaran RUBBERS Wilhelm Becker, Cologne-Mnlheim,and Alfred Blbmer, Imbach, near Opladen, Germany, assignors to I. G.Farbenindustrie Aktiengesellschaft, Frankiort-on-the-Main, Germany NoDrawing. Application November 6', 1933. serial nacsaaoa. .In GermanyApril as, 1932 3 Claims. (Cl..10623) such as methanol or ethanol. Thealkaline reacting substances maybe dissolved. in a suitable organicsolvent and may be then added to the precipitating bath. On the otherhand the alkation is complete the solution is heated to boiling linereacting substances may be made up to a concentrated aqueous solutionand then be added to the precipitating bath.

The solution of the chlorinated rubber is preferably treed from any freehydrochloric acid by a preliminary heating process and/or by reducingthe pressure.

A preferred way of carrying out our process comprises the step ofmaintaining the precipitated product for a prolonged time in thealkaline parts being by weight precipitating bath, ii desired, whileheating and adding, it necessary, a further quantity of alkalinereacting substances, in order to maintain tiliie alkaline reaction ofthe precipitating me- It is advantageous to run the solutions of thechlorinated rubber into a precipitating bath either in the diluted stateor in a comparatively slow manner.

In this way the chlorinated rubber is obtained in form 01' a finelygrained powder possessing a great surface.

Theproducts obtainable by our process yield-suitably after a shortwashing process, which may be carried out with the aid of methanol orwatenand after drying at a temperature, for instance, of 60 to 80C.-chlorinated rubber products which dissolve to clear solutions andrepresent in the dry state pure compounds of a high degree of stability.

The following examples illustratethe invention, without, however,limiting it thereto, the

Example -1 'A- solution or 25 parts or light crepe in 800 parts oi!carbon tetrachloride is chlorinated at 'room temperature. After thechlorination the with 560 parts of methanol, to which such an amount ofa methylalcoholic caustic potash solution is added that theprecipitating bath maintains an alkaline reaction after 15 hoursstirring at room temperature. Thereupon the I precipitated chlorinatedrubber is filtered by suction, washed with methanol and dried. The

product obtained is of a high degree of stability.

"Example 2 Into a solution of-100 parts of smoked sheets in 1500 partsof carbon tetrachloride 300 parts of chlorine are introduced. After thechlorinaat room temperature for 20 hours. The precipi- 0 I tated productis washed neutral with methanol and water and then dried at atemperature of Example 3 A solution of 25 parts 01'- light crepe in 800parts of carbon tetrachloride is chlorinated and then evaporated in thevacuo at. a temperature of 409 .q, to a content of 600 parts. Thesolution is then poured into methanol, to which pre- 3 vious to theprecipitation a sufllcient quantity of a 50%v caustic potash solutionhas been added. After standing for 15 hours the chlorinated rubber isfiltered by suction, washed with methanol and dried at a temperature of60 00.

Well stabilized chlorinated rubbers can also be obtained whensubstituting for the caustic alkalies, in the above examples, a sumcientquantity of guanidineor diphenylguanidine.

We claimz- 40 1. In the manufacture. oi chlorinated rubber an isolationand stabilization DIOCGSSl for the 1 the precipitating bath a pH valueof 11 or more,

thereby effecting instantaneous precipitation of the chlorinated rubberand maintaining the alkaline reaction or the-bath while it is in contactwith the precipitated product. 1 2. In the manufacture oi chlorinatedrubber" -an isolation and stabilization process for the product whichcomprises introducing organic solutions containing the same into aprecipitating bath comprising a water soluble alcohol and caustic alkaliin such a quantity as to impart to the precipitating bath a pH value of11 or more, thereby effecting instantaneous precipitation of thechlorinated rubber, and maintaining the alkaline reaction of the bathwhile it is in contact with the precipitated product.

. 3. In the manufacture of chlorinated rubber an isolation andstabilization process for the productwhich comprises introducing organicsoiutions containing the same into a precipitating WJLIIELM BECKER. 1

ALFRED BLOMER.

